Thankyou ft101 and skywardhunter!

Due to late flight booking and return date most likely to change I am on a flex plus ticket. I have in the past got the magic upgrade at the gate due to oversold economy (a big bonus on the dxb - akl flight).

Price wise if there is availability is it best to upgrade in lounge or once seated on flight?

am thinking of just paying to upgrade the dxb - akl flight then using points to upgrade on way home and of course changing days if need be to get availability for the upgrade.